To enhance the enjoyment of operating tracked vehicle toys such as model railroads, model highways, model ship canals, etc. accessory devices are operated at different points along the track. Toy persons that wave at the train, and power shovels that load trucks and cars are common examples of such accessories. To reduce the complexity of such track systems and to reduce cost, there has been a preference for powering such devices by the vehicle itself. This is done by mechanically stopping the powered vehicle at a selected point on the path so that the driven wheels of the vehicle stop on rollers that are driven by the wheels of the vehicle. These rollers in turn power the accessory, and for example, cause a toy merry-go-round to rotate. Heretofore these vehicle powered accessories have required a mechanical stop, for example, an upright post to be manually erected or withdrawn in order to stop the vehicle and then to allow it to proceed.